Sources of Individual Differences in Children's Understanding of Fractions

Longitudinal associations of domain‐general and numerical competencies with individual differences in children's understanding of fractions were investigated. Children (n = 163) were assessed at 6 years of age on domain‐general (nonverbal reasoning, language, attentive behavior, executive control, visual‐spatial memory) and numerical (number knowledge) competencies; at 7 years on whole‐number arithmetic computations and number line estimation; and at 10 years on fraction concepts. Mediation analyses controlling for general mathematics ability and general academic ability revealed that numerical and mathematical competencies were direct predictors of fraction concepts, whereas domain‐general competencies supported the acquisition of fraction concepts via whole‐number arithmetic computations or number line estimation. Results indicate multiple pathways to fraction competence.     

A systematic review of propulsion from the flutter kick – What can we learn from the dolphin kick?

Propulsion, one of the most important factors in front crawl swimming performance, is generated from both the upper and lower limbs, yet little is known about the mechanisms of propulsion from the alternating movements of the lower limbs in the flutter kick (FK). The purpose of this systematic review was to review the literature relating to the mechanisms of propulsion from FK in front crawl. There was limited information about the mechanisms of propulsion in FK. Since movements of the lower limbs are similar between FK and the dolphin kick (DK), mechanisms of propulsion from DK were reviewed to better understand propulsion from FK. Recent evidence suggests that propulsion in DK is generated in conjunction with formation and shedding of vortices. Similar vortex structures have been observed in FK. Visualisation and simulation techniques, such as particle image velocimetry (PIV) and computational fluid dynamics (CFD), are non-invasive tools that can effectively model water flow without impacting swimming technique. These technologies allow researchers to estimate the acceleration of water and, consequently, the propulsive reaction forces acting on the swimmer. Future research should use these technologies to investigate propulsion from FK.     

Cardiorespiratory and muscular fitness associations with older adolescent cognitive control

Background:Participation in physical activity supports greater cardiorespiratory fitness(CRF),a correlate of cognitive control.However,the relationship between muscular fitness(MF)and cognitive control is less clear.The present study investigated the differential relationship of CRF and MF with cognitive control in older adolescents.Methods:This cross-sectional study involved students(15
17 years old,n=541,43%female)from 20 secondary schools who completed tests of inhibition(modified flanker task),working memory(n-back task),CRF(Progressive Aerobic Cardiovascular Endurance Run),and MF(standing long jump and push-up test).Multilevel analyses tested the association between CRF or MF and cognitive outcomes while accounting for the influence of the other fitness variable and relevant demographic factors.Results:CRF predicted response accuracy during incongruent flanker trials,the condition requiring greater inhibition.For the working memory task,CRF predicted greater target accuracy and greater d’scores on the 1-back task,requiring lesser amounts of working memory.In the 2-back task,which requires greater amounts of working memory,CRF also predicted greater target and non-target accuracy and d’scores.Comparatively,MF did not predict any cognitive outcomes after adjustment for CRF.Conclusion:CRF was selectively related to better performance during task conditions that require greater amounts of inhibition and working memory.This finding suggests that CRF,but not MF,may benefit cognitive control in older adolescents.This selective influence of CRF on older adolescents’cognition highlights the value of aerobic physical activity.     

Perceptions of communication in a family relationship and the reduction of intergroup prejudice

From a contact theory perspective, links between variation in young adults' perceptions of communication with their grandparents and attitudes towards older adults are examined. The analysis pays particular attention to variation in communication with multiple grandparents, and finds links between that and perceived variability in the older adult population as a whole. More variation in perceptions of communication with grandparents is associated with perceptions of older adults as more heterogeneous. However, variation in grandparent relationships is associated with more negative attitudes towards older adults on measures of attitudinal central tendency. The results are discussed in terms of intergroup communication processes, contact theory and possible interventions to reduce prejudice in this and other contexts.     

Who Stole my Methodology? Co-opting PAR

As we enter the 21st century it seems likely that the collection of methodologies and methods that have constituted PAR will continue to permeate mainstream research. There is increasing evidence, for example, that the discourse of participatory action research is now being widely used by international development agencies, NGOs and related organisations to promote a wide array of educational, healthcare and social programmes. This paper argues that the increasing popularity and use of PAR over recent years poses both possibilities and problems for researchers. In particular, it will discuss the challenges that this process presents to the concept of participation within PAR, as well as the implications it has for constructing methodologies for inclusive forms of participatory research.     

Welche Zusammenhänge bestehen zwischen dem fachspezifischen Professionswissen von Mathematiklehrkräften und ihrer Ausbildung sowie beruflichen Fortbildung?

Zusammenfassung Der vorliegende Beitrag besch?ftigt sich aus der Perspektive von Theorien zum Kompetenzerwerb mit dem Zusammenhang zwischen dem fachspezifischen Professionswissen von Mathematiklehrkr?ften und ihrer Ausbildung und beruflichen Fortbildung. Dabei wurden institutionelle Unterschiede der Lehramtsausbildung wie auch individuelle Unterschiede im Studienerfolg, der Berufserfahrung und der besuchten beruflichen Fortbildungen untersucht. Die Analysen basieren auf Daten von 195 Mathematiklehrkr?ften, die an der COACTIV-Studie teilnahmen. Unsere Ergebnisse zeigen, dass sich Lehrkr?fte unterschiedlicher Lehr?mter deutlich in ihrem professionellen Wissen unterscheiden und dass insbesondere der Erfolg im Studium mit besseren Leistungen im Fachwissen und im fachdidaktischen Wissen zusammen hing. Wir diskutieren Implikationen unserer Ergebnisse vor dem Hintergrund der Lehramtsausbildung und beruflicher Fortbildungen.      

Retardation of rabbit nictitating membrane conditioning following US preexposures depends on the distribution and number of US presentations

Retarded conditioned response (CR) acquisition produced by unconditioned stimulus (US) preexposures has been attributed either to interference resulting from contextual conditioning or to habituation of the US. Both perspectives assume that the amount of retardation is directly related to the number of US preexposures. This assumption was examined in two experiments. In Experiment 1, separate groups of rabbits received 200 paraorbital shock US preexposures either in one session or spread equally over 10 daily sessions. Subsequently, all subjects received 150 CS-US pairings. Acquisition of nictitating membrane CRs was retarded relative to a naive control group only in the group that received the preexposures over 10 sessions. Thus, the number of US preexposure sessions, rather than the number of US preexposures, determined whether or not retarded acquisition was observed. In Experiment 2, four groups of rabbits received 1, 5, 20, or 40 shock US preexposures in each of 10 sessions. Over the subsequent 150 CS-US pairings, similar levels of retarded CR acquisition were observed in groups that received 20 and 40 US preexposures per session, a weak retardation effect was observed with 5 preexposures per session, and no retardation was observed with 1 preexposure per session. Thus, Experiment 2 suggested that retarded CR development was not greatly influenced by increasing the number of US preexposures above some minimum threshold number of exposures per session. Implications for current theories were discussed.     

What a Scientist Looks Like: How Community Colleges Can Utilize and Enhance Science Identity Development as a Means to Improve Success for Women of Color

ABSTRACT

This article explores the application of science identity development theory for women of color interested in the science disciplines; and it advocates for taking an intersectional approach to understanding how women of color form science identities. The article also challenges community college administrators and scholars to focus on redefining science identity development theory within the community college setting as a means to enhance success for women of color pursuing academic work in scientific disciplines.     

Understanding collaborative learning processes in new learning environments

Trying to understand the complexity of computer-mediated problem-based learning environments is not easy. Sociocultural theory provides a theoretical framework for understanding such environments because it emphasizes the socially situated nature of learning and the critical role of tools in mediating learning. To examine how different aspects of discourse relate to each other, as well as to the tools being used in the collaborative learning process, it is important to understand how collaborative knowledge building unfolds and how these processes are mediated. This requires going beyond coding individual speech acts. The use of Chronologically-Ordered Representations of Discourse and Tool-Related Activity (CORDTRA) diagrams is one way of achieving this understanding. We use this to study contrasting cases of more and less successful groups using the STELLAR learning environment. STELLAR is an integrated online PBL environment for preservice teachers, containing a learning sciences hypermedia, a library of videocases, and online personal and collaborative spaces. Our analyses suggest that an important locus of differences is how students use resources and engage in different kinds of metacognitive talk and knowledge transforming activities, sometimes to the group’s detriment. Frequency analyses provided an easily interpreted snapshot of each group’s activity. The CORDTRA analyses provide a more dynamic view that helps researchers and teachers better understand how collaborative learning unfolds. Such analyses have implications for understanding new learning environments as well as helping identify where interventions might be needed.